void quickSort(int *p, int low, int high)
{
    if(low<high)
    {
        int pivot = p[low];
        int l = low;
        int h = high;

        while(l<h)
        {
            while(p[h] >= pivot && l < h)
                h--;
            p[l] = p[h];

            while(p[l] <= pivot && l<h)
                l++;
        }
        //一圈完了之后 h==l 即为pivot该有的位置
        p[l] = pivot;

        //递归操作
        quickSort(p,low,h-1);
        quickSort(p,l+1,high);
    }
}